Dominion forces attack Deep Space Nine
Deep Space Nine's perimeter defenses destroy multiple Dominion ships
The Second Battle of Deep Space Nine was the opening battle of the Dominion War, in which the combined forces of the Dominion and the Cardassian Union, led by Gul Dukat, launched an assault on the Federation-held starbase Deep Space Nine. Although the station was captured by the Dominion, the battle was a strategic victory for the Federation because they successfully mind the Bajoran wormhole, preventing Dominion reinforcements from joining the battle from the Gamma Quadrant.
Beginning with the Dominion-Cardassian Alliance, the Dominion began to send massive amounts of vessels and material through the wormhole. Soon the sheer numbers of the Dominion forces in the Alpha Quadrant began to alarm Starfleet Command. A decision was made to mine the entrance to the wormhole to prevent these reinforcements. Maintenance engineer Rom suggested using self-replicating mines equipped with replicators and cloaking devices for the blockade. Thus, this minefield would be undetectable while allowing the ability to replace their numbers quickly and effectively. The USS Defiant immediately began laying down the minefield.
The action was seen as a provocation by the Dominion, who sent their representative Weyoun to Deep Space Nine to negotiate a decrease in tensions. Weyoun at first flatly demanded the cessation of the mining of the wormhole. Captain Sisko quickly refused. Weyoun then claimed the Cardassians, suffering the aftereffects of their war with the Klingons, needed the supplies the Dominion was providing. Captain Sisko bargained saying the Federation would remove the mines if the Dominion would restrict further convoys to nonmilitary personnel and materials. Both sides recognized this bargain as nothing more than a ruse to buy time - Weyoun to prepare the Dominion fleet for the attack.
With war imminent, Sisko, speaking both as a Starfleet Captain and Emissary of the Prophets, advised that the Bajoran Provisional Government sign the nonaggression pact offered to them by the Dominion, thus ensuring the safety of the planet and its people. First Minister Shakaar Edon agreed and the evacuation of all Bajorans from the station commenced.
Intent with opening the wormhole to Dominion traffic, the Dominion launched a massive attack on Deep Space Nine. The station was left without Starfleet reinforcements, with only the USS Defiant and the IKS Rotarran to supplement the station's defenses.
The Dominion assault force comprised of nearly 300 Jem'Hadar and Cardassian warships. Captain Sisko confidently rejected Dukat's offer to surrender. Five Jem'Hadar attack wings were sent to intercept the USS Defiant which was still completing the minefield. The IKS Rotarran provided interference and covering fire while the Defiant completed her mission. The minefield activated and immediately cloaked.
Dukat was able to cut main power to Deep Space Nine by targeting his weapons onto section 17 of the outer docking ring. With the wormhole mined and his defensive position untenable, Captain Sisko ordered the evacuation of Deep Space Nine. He left the station in the hands of his Bajoran liaison officer, Major Kira Nerys. Once the Defiant and the Rotarran had safely departed the station, Major Kira activated Program Sisko 197. This program completely sabotaged the station's computer and power systems, leaving the station a nearly lifeless hulk. The Dominion and Cardassian troops boarded the station without resistance.
Dukat and the Dominion may have captured Deep Space Nine from the Federation, but the price they paid of more than fifty Dominion ships destroyed ultimately provided them a pyrrhic victory. The minefield was deployed and cloaked preventing Dominion reinforcements from the Gamma Quadrant and a combined Starfleet-Klingon taskforce crossed the border into Cardassian territory and destroyed the shipyards at Torros III nearly unopposed. This victory seriously affected Dominion shipbuilding in the Alpha Quadrant.